export function buildTree(data: any, pid: number = 0) {
  let tree: any = [];

  data.forEach((node: any) => {
    if (node.pid == pid) {
      let children = buildTree(data, node.id);
      if (children.length) {
        node.children = children;
      }
      tree.push(node);
    }
  });
  return tree;
}
